The energy of a 50 kg student about to jump off a 1 meter counter
im confused what this means

Suppose you have three polarizing filters, with the second at an angle of 42∘ to the first and the third at an angle of 90∘ to the first. by what perfect will the original intensity of unpolarized light be reduced to after passing through all three filters?

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)

How to tell if two objects are in thermal equilibrium 1.the objects have the same temperature 2.the objects are the same size 3.the objects are touching each other 4.the objects temperatures are changing